Apparent wind direction indicators, generically referred to as masthead flys, typically consist of a vane on top of a short post atop the mast that rotates freely to point toward the apparent wind (which is a function of true wind direction/velocity, and boat speed/course). They provide a relative measure of wind direction which serves as reference point for trimming sails and choosing a course to steer the boat.
Masthead flys include two reference marks which have a fixed position approximately 145 degrees aft of dead ahead (forward), one mark to port and one to starboard. These reference marks are designed to allow the user to approximate whether the apparent wind angle is more, less, or the same as 35 degrees when sailing upwind, or 145 degrees when sailing downwind. These two reference marks are typically small squares constructed from, for example, cloth or plastic or alternatively these reference marks are the end of wire arms radiating from a post that holds the wind vane. These current designs make it very difficult to ensure any accuracy of the angles they are supposed to represent because the wires flex and their originating points are to close to the post and further because they rely upon the user approximating the angle when setting the reference marks.
Optimizing the speed of today's racing sailboats depends on relatively fine adjustments in course steered and sail trim relative to very small changes in wind direction and velocity, as can be indicated by an angle change in the vane of the masthead fly. Available masthead flys do not provide enough accuracy to assess these changes which occur continuously while sailing a race.
It it therefore an objective in the present invention to provide a device with improved accuracy of measuring apparent wind angles at the masthead, thereby significantly enhancing the user's ability to trim sails and steer the boat to achieve optimum speed through the water or speed towards the next mark of the course. It is further object of the present invention to provide such a device which is easy to manufacture and can therefore be manufactured at the lowest possible manufacturing cost so the wind indicator can be used by sailboats of all sizes.